Processing techniques are useful in many industries and can typically be accomplished by flowing a mixture of fluids over an active material, such as a catalyst or adsorbent material, to provide the preferred product stream. For adsorption process, the adsorbent materials preferentially adsorbs one or more gas components, while not adsorbing one or more other gas components. The non-adsorbed components are recovered as a separate product. For catalytic processes, the catalyst is configured to interact with the components in the stream to increase the rate of a chemical reaction.
By way of example, one particular type of gas separation technology is swing adsorption, such as temperature swing adsorption (TSA), pressure swing adsorption (PSA), partial pressure purge swing adsorption (PPSA), rapid cycle pressure swing adsorption (RCPSA), rapid cycle partial pressure swing adsorption (RCPPSA), and not limited to but also combinations of the fore mentioned processes, such as pressure and temperature swing adsorption. As an example, PSA processes rely on the phenomenon of gases being more readily adsorbed within the pore structure or free volume of an active material, such as an adsorbent material, when the gas is under pressure. That is, the higher the gas pressure, the greater the amount of readily-adsorbed gas adsorbed. When the pressure is reduced, the adsorbed component is released, or desorbed from the adsorbent material.
The swing adsorption processes (e.g., PSA and TSA) may be used to separate gases of a gas mixture because different gases tend to fill the micropore of the adsorbent material to different extents. For example, if a gas mixture, such as natural gas, is passed under pressure through a vessel containing an adsorbent material that is more selective towards carbon dioxide than it is for methane, at least a portion of the carbon dioxide is selectively adsorbed by the adsorbent material, and the gas exiting the vessel is enriched in methane. When the adsorbent material reaches the end of its capacity to adsorb carbon dioxide, it is regenerated in a PSA process, for example, by reducing the pressure, thereby releasing the adsorbed carbon dioxide. The adsorbent material is then typically purged and repressurized. Then, the adsorbent material is ready for another adsorption cycle.
Typically, the structures used in catalytic processes and adsorption processes have a limited array of physical structure types. The active material are often structured into beads, granules, spheres or pellets using binders and processing techniques like extrusion or spray drying. The beads, granules, spheres or pellets are then packed together within a unit as a packed bed for the catalytic or adsorption processes. As a result, the conventional fabrication of catalysts or adsorbents, involve extrusions of small sphere-like active materials to be used in packed beds (e.g., spheres, pellets, lobes, etc.). However, the packed beds provide tortuous paths through the packed bed, which result in large pressure drops.
In other configurations, the structure may be an engineered structure, such as a monolith. In engineered structures, the active materials are coated onto substrates, such as a metal or ceramic monolith. The engineered structures provide substantially uniform flow paths, which lessen pressure drops as compared to packed beds. However, with these structures the majority of weight is inactive material that is used to form the underlying support structure.
As a result, typical fabrication approaches of structures involve extrusions of small sphere-like active materials to be used in packed beds (e.g., spheres, pellets, lobes, etc.), or the application of thin coatings of active material on monolith substrates (e.g., ceramic or metal monoliths). The packed beds have large pressure drops as compared with engineered structures. Also, the engineered structures include additional weight from structural support that is inactive material, which increases the size and weight of the structure.
Other related materials include Rezaei, F. et al., 2009, Optimum structured adsorbents for gas separation processes, Chemical Engineering Science 64, p. 5182 to 5191; Patcas, F. C. et al., 2007, CO oxidation over structured carriers: A comparison of ceramic foams, honeycombs and beads, Chemical Engineering Science 62, p. 3984 to 3990; U.S. Patent Application Publication No. 20030145726; and Richardson, J. T. et al., 2000, Properties of ceramic foam catalyst supports: pressure drop, Applied Catalysis A: General 204, p. 19 to 32; and Stemmet, C. P. et al., 2006, Solid Foam Packings for Multiphase Reactors: Modelling of Liquid Holdup and Mass Transfer, Chemical Engineering Research and Design 84(A12), p 1134 to 1141.
Accordingly, there remains a need in the industry for apparatus, methods, and systems that provide enhancements in processes having self-supporting structures that include active materials and may include forming foam-geometry structures having complex geometries. Further, the present techniques provide enhancements by integrating self-supporting foam-geometry structures with adsorption or catalytic processes, such as swing adsorption processes to separate contaminants from a feed stream. Accordingly, the present techniques overcome the drawbacks of conventional structures in separation and/or catalysis processes.